This invention relates to medical devices in general, and more particularly to a device for positioning and tensioning a plurality of graft ligament strands simultaneously, equally, and to a selected tension.
It is known to use four combined strands, such as two (doubled) gracilis strands and two (doubled) semitendinosus strands, in reconstruction of the anterior cruciate ligament (ACL). It is further known to use other numbers of strands, such as one, two or three. It is also known to use other grafts, such as patellar tendon, quadriceps tendon, tibialis, and the like. When using more than one strand, it is preferred that the pluralities of ligament strands be equally tensioned, inasmuch as the strands must be under equal tension in order to provide optimum biomechanical properties. The tension on each ligament may be applied by hand one ligament at a time, but it has been demonstrated that applying tension by hand is not effective in equalizing the load on the various tendon strands. An improvement has been realized by tensioning the strands with applied weights as, for example, by hanging a weight from each tendon strand. While the use of such weights provides a known tension and equalization of tensions, the handling of the weights in the course of an ACL reconstruction has proven awkward and laborious.
Accordingly, there is a need for a device by which a plurality of graft ligament strands may be tensioned simultaneously, equally, to a desired tension, and positioned to a desired orientation.
An object of the invention is to provide a graft ligament strand tensioner having facility for tensioning one or a plurality of graft ligament strands simultaneously, equally, and to a selected tension, and to a desired position.
Another object of the invention is to provide an improved method for reconstructing a ligament.
With the above and other objects in view, as will hereinafter appear, a feature of the invention is the provision and use of a graft ligament strand tensioner comprising a frame member for slidingly retaining loops of suture strands attached to and extending from the ligament strands and having a collar portion, a cylinder having a spherical portion and on which the collar portion is mounted for pivoting movement, a grip portion for manipulation by an operator to apply tension to the strands, a stop member connected to the cylinder, and a spring disposed within a space between the grip portion and the cylinder, the spring being retained by the stop member. The collar portion is tiltingly movable on the cylinder member spherical portion surfaces when manipulation of the grip portion, to pull strands on the frame member taut, causes the stop member to compress the spring portion. The sliding retention of the strands and the pivoting movement of the collar portion provide substantial equalization of tension in the strands.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.